C# 以黑白方式呈现照片

【核心代码】

using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;

namespace Image
{
	/// <summary>
	/// Form1 的摘要说明。
	/// </summary>
	public class Form1 : System.Windows.Forms.Form
	{
		private System.Windows.Forms.Button button1;
		private System.Windows.Forms.OpenFileDialog openFileDialog1;
		private System.Windows.Forms.PictureBox pictureBox1;
		private System.Windows.Forms.Button button2;
		/// <summary>
		/// 必需的设计器变量。
		/// </summary>
		private System.ComponentModel.Container components = null;

		public Form1()
		{
			//
			// Windows 窗体设计器支持所必需的
			//
			InitializeComponent();

			//
			// TODO: 在 InitializeComponent 调用后添加任何构造函数代码
			//
		}

		/// <summary>
		/// 清理所有正在使用的资源。
		/// </summary>
		protected override void Dispose( bool disposing )
		{
			if( disposing )
			{
				if (components != null) 
				{
					components.Dispose();
				}
			}
			base.Dispose( disposing );
		}

		#region Windows 窗体设计器生成的代码
		/// <summary>
		/// 设计器支持所需的方法 - 不要使用代码编辑器修改
		/// 此方法的内容。
		/// </summary>
		private void InitializeComponent()
		{
			System.Resources.ResourceManager resources = new System.Resources.ResourceManager(typeof(Form1));
			this.button1 = new System.Windows.Forms.Button();
			this.openFileDialog1 = new System.Windows.Forms.OpenFileDialog();
			this.pictureBox1 = new System.Windows.Forms.PictureBox();
			this.button2 = new System.Windows.Forms.Button();
			this.SuspendLayout();
			// 
			// button1
			// 
			this.button1.Location = new System.Drawing.Point(48, 168);
			this.button1.Name = "button1";
			this.button1.Size = new System.Drawing.Size(80, 23);
			this.button1.TabIndex = 1;
			this.button1.Text = "浏览图像";
			this.button1.Click  = new System.EventHandler(this.button1_Click);
			// 
			// openFileDialog1
			// 
			this.openFileDialog1.Filter = "Image files (JPeg, Gif, Bmp, etc.)|*.jpg;*.jpeg;*.gif;*.bmp;*.tif; *.tiff; *.png|"  
				" JPeg files (*.jpg;*.jpeg)|*.jpg;*.jpeg |GIF files (*.gif)|*.gif |BMP files (*.b"  
				"mp)|*.bmp|Tiff files (*.tif;*.tiff)|*.tif;*.tiff|Png files (*.png)| *.png |All f"  
				"iles (*.*)|*.*";
			// 
			// pictureBox1
			// 
			this.pictureBox1.BorderStyle = System.Windows.Forms.BorderStyle.Fixed3D;
			this.pictureBox1.Image = ((System.Drawing.Image)(resources.GetObject("pictureBox1.Image")));
			this.pictureBox1.Location = new System.Drawing.Point(8, 8);
			this.pictureBox1.Name = "pictureBox1";
			this.pictureBox1.Size = new System.Drawing.Size(296, 152);
			this.pictureBox1.TabIndex = 3;
			this.pictureBox1.TabStop = false;
			// 
			// button2
			// 
			this.button2.Location = new System.Drawing.Point(176, 168);
			this.button2.Name = "button2";
			this.button2.Size = new System.Drawing.Size(80, 23);
			this.button2.TabIndex = 4;
			this.button2.Text = "黑白图像";
			this.button2.Click  = new System.EventHandler(this.button2_Click);
			// 
			// Form1
			// 
			this.AutoScaleBaseSize = new System.Drawing.Size(6, 14);
			this.BackColor = System.Drawing.Color.FromArgb(((System.Byte)(224)), ((System.Byte)(224)), ((System.Byte)(224)));
			this.ClientSize = new System.Drawing.Size(312, 198);
			this.Controls.Add(this.button2);
			this.Controls.Add(this.pictureBox1);
			this.Controls.Add(this.button1);
			this.MaximizeBox = false;
			this.Name = "Form1";
			this.StartPosition = System.Windows.Forms.FormStartPosition.CenterScreen;
			this.Text = "演示图像黑白显示";
			this.ResumeLayout(false);

		}
		#endregion

		/// <summary>
		/// 应用程序的主入口点。
		/// </summary>
		[STAThread]
		static void Main() 
		{
			Application.Run(new Form1());
		}

		private void button1_Click(object sender, System.EventArgs e)
		{//浏览图像文件
			this.openFileDialog1.ShowDialog();
			if(this.openFileDialog1.FileName.Trim()=="")
				return;
			try
			{   
				Bitmap MyBitmap=new Bitmap(this.openFileDialog1.FileName);
				this.pictureBox1.Image=MyBitmap;
			}
			catch(Exception Err)
			{
				MessageBox.Show(this,"打开图像文件错误！","信息提示",MessageBoxButtons.OK,MessageBoxIcon.Information);
			}
		}
		private void button2_Click(object sender, System.EventArgs e)
		{//以黑白方式显示图像			
			int Height=this.pictureBox1.Image.Height;
			int Width=this.pictureBox1.Image.Width;
			Bitmap bitmap=new Bitmap(Width,Height);
			Bitmap MyBitmap=(Bitmap)this.pictureBox1.Image;
			Color pixel; 
		    for (int x=0; x<Width; x  ) 
					for (int y=0; y<Height; y  ) 
					{
						pixel=MyBitmap.GetPixel(x,y);
						int r,g,b,Result=0;
						r = pixel.R;							
						g = pixel.G;				
						b = pixel.B;	
						//实例程序以加权平均值法产生黑白图像
						int iType=2;
						switch(iType)
						{
							case 0://平均值法
								Result=((r g b)/3);
								break;
							case 1://最大值法
								Result=r>g?r:g;
								Result=Result>b?Result:b;
								break;
							case 2://加权平均值法
								Result=((int)(0.7*r) (int)(0.2*g) (int)(0.1*b));
								break;
						}
					    bitmap.SetPixel(x,y,Color.FromArgb(Result,Result,Result));
					}	 
			this.pictureBox1.Image=bitmap;		
		}
	}
}